[Marilize]

Well done for rescuing a little one.

I just want to add a practical tip:
If your doggie is food motivated (meaning that he likes treats and will do something to get them), you can try a treat ball. By putting the treats inside, he has to roll the ball to get the treats out. In this way, he will positively associate the toy with something good.
When you get the ball, fill it with treats and show it to your baby. Roll it around so that he sees that the treats come out. Do this only once, you want him to do it himself.
If he doesn't take to the ball in a few minutes, leave it with him for a little while and then take it away.
To help him take to it the next time, maybe skip breakfast so that he is hungry and fill the ball with his food, but make it yummy. Some peanut butter or cheese spread works well.

Hope this helps.

Ps. Both of mine are crazy about their toys and they play with themselves, together or with me. If they aren't sleeping, they are playing with their toys.